[Why]
When mpo enabled, video comes is 709. Desktop use sRGB.
So color change easily noticeable especially when switch between
mpo/non-mpo.

[How]
Force use sRGB for video TF is sRGB or BT709.
DCN1/DCN2 use predefined type with YUV.
DCN3 use distributed points type with YUV.
Signed-off-by: Jing Zhou <Jing.Zhou@amd.com>
Acked-by: Bindu Ramamurthy <bindu.r@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>